U.S. patent application number 12/026040 was filed with the patent office on 2009-08-06 for patterned wavelength converting structure.
This patent application is currently assigned to Kismart Corporation. Invention is credited to Chun-Chung Hsiao, Hsin-Tao Huang.
Application Number | 20090196014 12/026040 |
Document ID | / |
Family ID | 40931493 |
Filed Date | 2009-08-06 |
United States Patent
Application |
20090196014 |
Kind Code |
A1 |
Hsiao; Chun-Chung ; et
al. |
August 6, 2009 |
PATTERNED WAVELENGTH CONVERTING STRUCTURE
Abstract
The present invention provides a patterned wavelength converting
structure comprising a frame, a light source, a substrate, a film,
a wavelength converting layer and a pattern disposed on the film.
The pattern and the wavelength converting layer can be one piece.
The configuration, for example, the distribution of diffusion
particles, the location, the shape or the thickness, of the pattern
is configured to reduce the mura or affect the desired uniformity
of a lighting area.
Inventors: |
Hsiao; Chun-Chung; (Caotun
Township, TW) ; Huang; Hsin-Tao; (Zhubei City,
TW) |
Correspondence
Address: |
KUSNER & JAFFE;HIGHLAND PLACE SUITE 310
6151 WILSON MILLS ROAD
HIGHLAND HEIGHTS
OH
44143
US
|
Assignee: |
Kismart Corporation
|
Family ID: |
40931493 |
Appl. No.: |
12/026040 |
Filed: |
February 5, 2008 |
Current U.S.
Class: |
362/84 |
Current CPC
Class: |
B82Y 20/00 20130101;
G02F 2202/28 20130101; G02F 2201/086 20130101; G02F 1/133545
20210101; G02F 2201/54 20130101; G02F 1/017 20130101; G02F 1/133611
20130101; G02F 1/133614 20210101 |
Class at
Publication: |
362/84 |
International
Class: |
F21V 9/16 20060101
F21V009/16 |
Claims
1. A patterned wavelength converting structure comprising: a light
source; a substrate disposed upon said light source; a wavelength
converter positioned over a surface of said substrate near said
light source; and a pattern with a specific configuration
positioned over one surface of said substrate for a surface of a
wavelength converting layer for reducing the mura effect or affect
of the distribution of non-uniformity of light, wherein said
configuration of said pattern determines aimed luminance at a
corresponding position of a lighting area.
2. The patterned wavelength converting structure of claim 1,
wherein said pattern is positioned on one surface of said
wavelength converter.
3. The patterned wavelength converting structure of claim 2,
wherein said pattern and said wavelength converting layer is one
piece.
4. (canceled)
5. The patterned wavelength converting structure of claim 1,
wherein said configuration is the shape of said pattern.
6. The patterned wavelength converting structure of claim 5,
wherein said shape is a strip, a collection of dots, or a
combination thereof.
7. The patterned wavelength converting structure of claim 1,
wherein said configuration is the thickness of said pattern.
8. The patterned wavelength converting structure of claim 1,
wherein said configuration is the location of said pattern.
9. The patterned wavelength converting structure of claim 1,
wherein the material character of said pattern also determines the
aimed mura at the corresponding position of a lighting area.
10. The patterned wavelength converting structure of claim 9,
wherein said character is the density distribution of diffusion
particles of said material.
11-18. (canceled)
19. The patterned wavelength converting structure of claim 1,
wherein said pattern is made by a phosphor material, a photo
luminescent material, a fluorescent color-conversion-media, an
organic complex material, a luminescent pigment(s), a quantum
dots-based material, a quantum wire-based material, or a quantum
well-based material, the combination thereof or the materials
suitable for converting the incident light into aimed
wavelength.
20. The patterned wavelength converting structure of claim 1,
further comprising a first film positioned between said wavelength
converter and said substrate.
21. The patterned wavelength converting structure of claim 20,
wherein said pattern is positioned on one surface of said
wavelength converter.
22. The patterned wavelength converting structure of claim 20,
wherein said pattern is positioned on one surface of said first
film.
23. The patterned wavelength converting structure of claim 20,
further comprising a second film positioned on the surface of said
substrate opposite to the surface facing said first film, and said
pattern is positioned on one surface of said second film.
24. The patterned wavelength converting structure of claim 20,
further comprising a second film positioned between said substrate
and said first film, and said pattern is positioned between said
second film and said second film.
25. The patterned wavelength converting structure of claim 20,
wherein said first film is flexible.
26. The patterned wavelength converting structure of claim 23,
wherein said first film, said second film or both are flexible.
27. The patterned wavelength converting structure of claim 24,
wherein said first film, said second film or both are flexible.
28. The patterned wavelength converting structure of claim 20,
further comprising an adhesive layer for fixing said first
film.
29. The patterned wavelength converting structure of claim 23,
further comprising an adhesive layer for fixing said first film,
second film or both.
30. The patterned wavelength converting structure of claim 24,
further comprising an adhesive layer for fixing said first film,
second film or both.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a wavelength converting
structure and more particularly to a patterned wavelength
converting structure for reducing mura or for affecting mura
distribution of a lighting area.
BACKGROUND OF THE INVENTION
[0002] Taking a cold cathode fluorescent lamp CCFL as a light
source has the shortcomings as below. The CCFL emits light with
wavelength 185 nm which causes a new absorptive spectrum band and
the brightness of emitting light degrades with time; the
recombination of Hg.sup.+ and the other ions at the tube wall
disrupts the lattice structure of the phosphor layer exaggerating
the brightness degradation of the emitting light. Moreover, for
CCFL, the phosphor coating and the light emitting source have to be
disposed in the same vacuum lamp tube, and therefore it is
difficult to produce large-sized lamps and to provide a wavelength
conversion structure with large emitting area only by CCFL. Another
disadvantage is that the phosphor coating mentioned above is uneven
in most cases. Therefore, the light emitted by the CCFL suffers the
problem of non-uniformity.
[0003] Other light sources, including external electrode
fluorescent lamps (EEFL), light emitting diodes (LED), carbon
nanotubes (CNT), flat fluorescent lamps (FFL), and organic light
emitting displays (OLED) are either immature for production (e.g.,
LED, CNT, OLED and FFL) or inapplicable for large-size
applications. More importantly, being a flat light source, these
existing light sources are expensive and complex.
[0004] The light sources mentioned above are line source or point
source. If the distance between the light sources mentioned above
is too far or the distance between the light source and a diffusion
plate or a guiding plate is too narrow, a phenomenon called "mura"
appears or becomes exaggerated. Mura effect is a problem that
should be paid attention to while utilizing the traditional light
sources listed above for producing a light source with uniformity.
Mura effect here means the luminance difference of a lighting area.
The phenomenon may be caused by reflection of incident light,
interaction of light field, position of the light sources, for
example, interference of light, luminance distribution, or
both.
[0005] FIG. 1 discloses a flat light source 1 having a light
emitting layer 11, a diffusion plate 12 for diffusing the incident
light, lamps 13 and other optical structures 14. The flat light
source 1 is designed for providing emitting light with lowered
mura. Referring to FIG. 2, the non-uniformity ratio of the emitting
light provided by the flat light source is lowered while the
diffusion angle is lower than about 150 degree, but the emitting
light provided by such a flat light source still suffers from
undesired mura effect.
[0006] To provide a light source with less mura, the traditional
way is to provide a diffusion plate or an optical structure with
ink printed on the surface. Both solutions lower the luminance of
emitting light, and the latter solution also requires aligning the
position of ink with the light source with high precision.
[0007] Many inventions have been provided, too. Some inventions
relate to improving the optical character of the diffusion plate.
U.S. Pat. No. 7,290,921 provides a light guide plate with
sub-scattering-dots for producing uniform emitting light. The
technical feature of this invention is providing scattering-dots
and sub-scattering-dots at a predetermined region on the bottom
surface of said light guide; wherein at least one
sub-scattering-dot is disposed around each scattering-dot and the
sub-scattering-dots are smaller than the scattering-dots. U.S. Pat.
No. 7,018,059 provides a direct type backlight module; wherein, a
diffuser plate disposed on the reflector, and the lamps are
disposed between the reflector and the diffuser plate. This
invention provides a light-distributing device to inhibit mura
effect. The light distributing device is a prism plate, a metallic
adhesive layer with a plurality of holes or a light guide plate
with various indexes of refraction thereon.
[0008] Some inventions provide improvement of the surface
character. U.S. Pat. No. 7,172,331 provides a direct type backlight
module having a holding structure for holding a reflector on a
frame, instead of using an adhesive to prevent roughness and
unevenness in the reflector's surface when the reflector is
attached onto the surface of the frame.
[0009] In view of the above, no invention has been found relating
to controlling the mura of a lighting area by manipulating the
configuration of a wavelength converting structure. Therefore, a
patterned wavelength converting structure is disclosed herein.
SUMMARY OF THE INVENTION
[0010] One advantage of the present invention is providing a
patterned wavelength converting structure for affecting mura
distribution of a lighting area.
[0011] Another advantage of the present invention is providing a
patterned wavelength converting structure with a pattern for
reducing mura of a lighting area.
[0012] Another advantage of the present invention is providing a
patterned wavelength converting structure with lower cost, and
preventing undesired warping of the structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates a cross-sectional view of a flat
wavelength converting structure;
[0014] FIG. 2 illustrates the non-uniformity ratio of the emitting
light of the flat light source and the CCFL;
[0015] FIG. 3 illustrates a cross-sectional view of a wavelength
converting structure with pattern;
[0016] FIG. 4 illustrates the relation of the thickness of the
material with the transmittance of light;
[0017] FIG. 5 illustrates the luminance difference of the emitting
light before and after the pattern is formed;
[0018] FIG. 6 illustrates the location of the pattern;
[0019] FIG. 7 illustrates the location of the pattern;
[0020] FIG. 8 illustrates the location of the pattern;
[0021] FIG. 9 illustrates the location of the pattern; and
[0022] FIG. 10 illustrates the location of the pattern.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] The invention will now be described in greater detail with
preferred embodiments of the invention and illustrations attached.
Nevertheless, it should be recognized that the preferred
embodiments of the invention are only for illustration. Besides the
preferred embodiments mentioned here, the present invention can be
practiced in a wide range of other embodiments besides those
explicitly described, and the scope of the present invention is
expressly not limited by the embodiments but determined by the
accompanying claims.
[0024] The description hereafter relates to embodiments of the
present invention. Some structure and functional details of the
patterned wavelength converting structure are described in U.S.
patent application Ser. No. 11/940,845 "Flat Converting Structure
and Manufacture and Use of the Same" fully incorporated herein by
reference in its entirety.
[0025] FIG. 3 discloses a flat light source 2 including a light
source 20 disposed inside a frame (not shown) and a patterned
wavelength converting structure 21 for producing light with low
mura. The light source 20 is for providing incident light to the
patterned wavelength converting structure 21. In one embodiment,
the light source 20 is an UVc lamp, where UVc denotes the
wavelength ranges no more than 280 nm. In another embodiment, the
range of the wavelength falls between 200 nm to 280 nm, and, more
particularly, from 250 nm to 260 nm; the preferred wavelength being
253.7 nm. In another embodiment, the light source 20 emits light
other than UVc light, e.g., the light source 20 is an LED or other
lighting device, as long as the emitting light is suitable for the
corresponding converting structure 21 to provide light with the
aimed wavelength.
[0026] The patterned wavelength converting structure 21 includes a
substrate 22, an adhesive layer 23, a film 24 that sticks on the
substrate 22 by adhesive layer 23, and a wavelength converting
layer 25 for converting the wavelength of incident light into the
aimed wavelength and producing a uniform lighting area, a pattern
26 for further reducing mura effect. In one embodiment, the
wavelength converting layer 25 is the phosphor layer disclosed by
U.S. patent application Ser. No. 11/940,845. In a preferred
embodiment, the wavelength converting layer 25 is a layer of
phosphor excitable by UVc light to provide visible light.
[0027] The pattern 26 is a strip structure made of a material with
uniform density of diffusion particles and aligns to the light
source 20; wherein the transmittance of light is inverse
proportional to the thickness of the material according to FIG. 4.
FIG. 5 illustrates the luminance difference of the emitting light
before and after the pattern 26 is formed. According to FIG. 5, the
luminance difference drops after the pattern 26 is formed; wherein
.tangle-solidup. denotes the luminance distribution of the light
emitted by the converting structure and .box-solid. denotes the
luminance distribution of the light emitted by the converting
structure with pattern 26.
[0028] The description hereafter discloses other embodiments but
not limiting. Referring to FIG. 3 again, the converting structure
21 is for, but not limited to, converting the wavelength of the
incident light into the emitting light with the aimed wavelength,
for guiding the incident light and for acting as a planar light
source emitting uniform light.
[0029] The patterned wavelength converting structure 21 is a
composite structure comprising a substrate 22, an adhesive layer
23, a film 24 that sticks on the substrate 22 by adhesive layer 23,
a wavelength converting layer 25 for converting the wavelength of
incident light into aimed wavelength and producing uniform lighting
area, a pattern 26 for further reducing mura effect of lighting
area.
[0030] In one embodiment of the present invention, the pattern 26
can be made by a photo luminescent material, a fluorescent
color-conversion-media, an organic complex material, a luminescent
pigment(s), a quantum dots-based material, a quantum wire-based
material, or a quantum well-based material or the combination
thereof, as long as the materials of the converting structure are
suitable for converting incident light into aimed wavelength.
[0031] The wavelength converting layer 25 disclosed by the present
invention is also a layer with the pattern 26 for reducing mura
effect; that is, the surface of the wavelength converting layer 25
is arranged with a specially arranged contour, profile or patterns
at a specific area to acquire a uniform lighting area.
[0032] The pattern 26 means the patterns of the patterned
wavelength converting layer 25, a structure or printed pattern
formed on the wavelength converting layer 25, or the combination
thereof for reducing mura effect. In a preferred embodiment, the
pattern and the wavelength converting layer is formed in one piece;
for example, the wavelength converting layer and the pattern formed
thereon is printed or coated on the film. Because the structure is
formed without curing, compared with the optical structure having a
pattern formed thereon by printing, the structure disclosed by the
present invention has the benefit of forming without undesired
warping.
[0033] The configuration of the pattern 26 aims to reducing mura
effect. In one embodiment, the pattern 26 is arranged according to
the mura distribution of the lighting area and/or the distribution
of the light sources. In another embodiment, the thickness of the
pattern 26 at the specific area is determined according to the
luminance at that area for producing a uniform lighting area. In
another embodiment, the thickness of the material of the pattern 26
is inverse proportional to the transmittance of light according to
FIG. 4. In another embodiment, the shape of the pattern 26 at
specific area is another factor for providing a lighting area with
low mura; for example, the shape of the pattern 26 can be an area
with uniform composition, an area formed by multiple mesh points,
or a combination thereof.
[0034] Material of the pattern 26 is another factor for providing a
uniform lighting area. In one embodiment, the material of the
pattern 26 is the same as the wavelength converting layer 25. In
another embodiment, the material of pattern 26 is the same material
as that of the substrate 22 or other materials suitable for
diffusing incident light. In another embodiment, the mura effect of
the lighting area is controlled by the characters of the material
forming the pattern 26; for example, in one embodiment, the
transmittance of light is determined by the density of the
diffusion particle at that area. In another embodiment, the
characters may comprise the reflective index, the transparency or
other optical characters relating to the diffusion effect of the
incident light.
[0035] The pattern 26 can also be a combination structure to
provide a lighting area with lowered mura. In another embodiment,
the pattern 26 is an optical structure with multiple layers and
each layer is not necessarily the same. In another embodiment, the
wavelength converting structure can be divided into several regions
with different materials, patterns, refractive index, other optical
characters relating to luminance of light or combination thereof
according to the embodiment.
[0036] According to the FIGS. 6-8, the location of pattern 26 in
the converting structure 21 is another factor relating to the
uniformity of a lighting area. In FIG. 3, the pattern 26 is an
optical structure attached to the surface of wavelength converting
layer 25. In FIGS. 6-10, 20 is the light source. In FIG. 6 the
pattern 26 is formed on the surface of film 24 opposite to the
surface that the wavelength converting layer 25 is disposed on, and
covered by the substrate 22; wherein an adhesive layer 23 is
applied between the substrate 22 and the film 24.
[0037] In FIG. 7, the pattern 26 is formed on the lower surface of
the film 241 and the upper surface of the film 241 is fixed on the
substrate 22 via adhesive layer 231. The film 24 with the
wavelength converting structure 25 disposed thereon is fixed on the
lower surface of the film 241 via adhesive layer 23.
[0038] In FIG. 8, the wavelength converting layer 25 is formed on
the lower surface of the film 24. The pattern 26 is formed on the
substrate 22 and covered by the film 24. The film 24 with the
wavelength converting structure 25 disposed thereon is fixed on the
lower surface of the substrate 22 via adhesive layer 23.
[0039] FIG. 9 illustrates another embodiment of the present
invention. The wavelength converting layer 25 is formed on the
lower surface of the film 24. The pattern 26 is fixed on the upper
surface of the substrate 22, and the film 24 with the wavelength
converting structure 25 disposed thereon is fixed on the lower
surface of the substrate 22 via adhesive layer 23.
[0040] FIG. 10 illustrates another modification of the present
invention. The wavelength converting layer 25 is formed on the
lower surface of the film 24, and the upper surface of the film 24
is attached on the lower surface of the substrate 22 via an
adhesive layer 23. Another film 241 is attached on the upper
surface of the substrate 22. An adhesive layer 231 is applied
between the substrate 22 and the film 241. The pattern 26 is
disposed on the upper surface of the film 241 without adhesive.
[0041] Referring to FIG. 3 again, the present invention also
discloses a wavelength converting layer 25 with pattern 26 for
providing a lighting area with required mura effect. The
configuration of pattern 26 is arranged according to the mura
distribution of a lighting area. In one embodiment the material
thickness, shape, location or the combination thereof of pattern 26
at a specific area is determined according to the luminance at that
area for obtaining emitting lighting area specific mura pattern.
For example, the thickness of pattern 26 is variant for producing a
lighting area with required mura effect correspondent to the
thickness of the pattern 26. In another embodiment, the
characteristics of the material relating to luminance of a lighting
area may comprise density, reflective index, the transparency, or
other optical characters are other factors for providing a lighting
area with required mura.
[0042] The pattern 26 can also be a combination structure to
provide required mura effect, for example, the pattern 26 can be an
optical structure with multiple layers and each layer is not
necessarily the same.
[0043] The pattern 26 can also be formed according to the range of
tolerable mura effect, which means the configuration, for example,
the thickness, shape, location or any combination thereof of the
pattern 26 may not exactly be determined by the distribution of
mura distribution of a lighting area, as long as the pattern 26 can
produce light with the required mura effect. In another embodiment,
the mura of a lighting area is controlled by the characteristics of
the material forming the pattern 26, for example, the reflective
index, the density, or other optical characters relating to the
diffusion effect of light.
[0044] The adhesive layer 23 disclosed by the present invention is
a macromolecular material. In another embodiment, the preferred
adhesive is an anti-UVC material for preventing the yellowing of
the wavelength converting coating and the degradation of the
adhesive itself. The material of the adhesive layer is disclosed in
U.S. patent application Ser. No. 11/940,845 fully incorporated
herein by reference.
[0045] The patterned wavelength converting structure disclosed by
the present invention also comprises optical structures for
changing the optical property of the emitting light, for example,
the uniformity, brightness, polarization or any combination
thereof. The optical structure may comprise any appropriate optical
elements, for example, a prism, an optical film or sheet such as a
diffusion plate, a diffusion film, a brightness enhancement film
(BEF), a dual brightness enhancement film (DBEF), a prism plate, a
lenticular film, a polarizer, a diffusion plate with screen
printing or any combinations thereof.
[0046] The present embodiment also discloses a UV-blocking coating
which is disclosed in U.S. patent application Ser. No. 11/940,845
fully incorporated herein by reference.
[0047] In another embodiment, the present invention also discloses
a patterned wavelength converting structure comprising a frame, a
light source disposed inside the frame; a substrate disposed above
the light source, a film disposed on the substrate, a converter
disposed on the film comprising a wavelength converting layer and a
pattern formed on the surface of the wavelength converting layer
for producing the desired mura or reducing mura at a lighting area.
The patterned wavelength converting structure disclosed by the
present invention also comprises optical structures for changing
the optical property of the emitting light.
[0048] The present invention also discloses a method for forming
patterned wavelength converting structure disclosed herein.
[0049] The present invention discloses a method for forming a light
source including an UVc lamp and a wavelength converting layer
excitable by UVc light to provide the desired emitting light. In
one embodiment, the wavelength converting layer comprises a
phosphor layer. The process for forming a phosphor layer is
disclosed by U.S. patent application Ser. No. 11/940,845 "Flat
converting structure and Manufacture and Use of the Same" fully
incorporated herein by reference in its entirety.
[0050] Because the material of the film is flexible, the phosphor
layer is applied on the substrate plate by coating; for example,
dip coating, comma coating, spraying coating, spin coating, slot
coating, curtain coating, gravure coating, or meyer rod coating.
Alternatively, the phosphor layer can also be applied by printing,
tapping, molding, or inject molding.
[0051] The pattern and the wavelength converting layer is formed in
one piece, for example, the converting layer and a strip pattern
formed thereon is printed or coated on the film in one piece. In
another embodiment, the pattern is formed by attachment. In another
embodiment, the contour or profile of the pattern can be configured
by adjusting the mouth shape of output for forming the wavelength
converting layer.
[0052] The material of the phosphor layer contains a binder, for
example, the binder disclosed in U.S. patent application Ser. No.
11/940,845, and therefore the phosphor layer is attached on the
film without applying an adhesive. In another embodiment, the
pattern is attached on a substrate by adhesive.
[0053] Next, the prepared wavelength converting layer, that is, the
substrate and the phosphor layer, is disposed in front of the
emitting light path of the UVc lamp, and then the other optical
structures are disposed on the substrate; wherein an adhesive layer
is applied between layers if necessary.
[0054] The configuration of the pattern structure also relates to
reducing mura effect. In one embodiment, the pattern is arranged
according to the mura distribution of the lighting area. The
parameters for deciding the configuration of the pattern comprising
the dimension, distribution, selected material, density of
distribution, the location of the wavelength converting layer
mentioned above and etc. These manufacturing parameters can be
controlled while performing manufacturing process of wavelength
converting layer and then the pattern can be formed with the
phosphor layer in one piece or formed in different pieces for
combining with the phosphor layer later.
[0055] In another embodiment, the present invention discloses the
wavelength converting layer comprising a layer for photo
luminescent, a fluorescent color-conversion-media, an organic
complex structure, a luminescent pigment(s), a quantum dots-based
structure, a quantum wire-based structure, or a quantum well-based
structure or the combination thereof, as long as the materials of
the converting structure are suitable for converting incident light
into aimed wavelength. The preparing and patterning of the
wavelength converting layer is performed according to the known
method or the preparing method disclosed above. For example, in
another embodiment, the patterns can also be formed at the location
other than the surface of the wavelength converting layer; the
patterned structure can be disposed between any optical structures
or on an optical structure as illustrated in FIG. 6 to FIG. 8. It
is noteworthy that an adhesive, for example, PMA, is provided if it
is necessary.
[0056] Although preferred embodiments of the present invention have
been described, it will be understood by those skilled in the art
that the present invention should not be limited to the described
preferred embodiments. Rather, various changes and modifications
can be made within the spirit and scope of the present invention,
as defined by the following claims.
* * * * *